Energy storage requirements continue to grow as the electronic, portable power, and energy infrastructure industries expand and transition away from more historic non-renewable energy supplies. For example, there has been a renewed interest in batteries, fuel cells, and other energy storage devices for use in electric and hybrid automobiles. Similarly, there is ongoing research in ways to make lighter and more efficient batteries for electronic devices ranging from portable computers to cellular phones and other wireless communication devices. General goals for battery manufacturers include providing long life and significant power levels with the least amount of weight.
More specifically, one of the most critical parameters for new energy storage technologies and designs is the demand for higher energy densities (i.e., energy storage per unit of battery or storage device weight). Additionally, there is growing concern over potential long term environmental impacts of product manufacture and use, and, the energy storage industry continues to search for storage devices that can make use of environmentally benign materials while still providing desirable energy densities.
Over the past fifty years, lithium-based energy storage technologies have become preeminent for use in providing portable power, which is due, in large part, to the relatively high energy density obtainable with lithium. Hydrogen may provide improved lightweight energy storage when compared with lithium because hydrogen is the lightest element and has energy densities of up to 40,000 Watt hours per kilogram (WH/Kg). Hydrogen-based energy storage is presently being heavily investigated with much of the research concentrating on the use of hydrogen in fuel cell applications.
However, a number of problems have made use of hydrogen difficult for energy storage devices. For example, problems with using hydrogen in fuel cells include substantial cost, durability of cells, temperatures that differ significantly from ambient temperatures, and hydrogen storage issues. Hydrogen fuel cells have yet to be designed that are cost effective to produce, use, and maintain. This is in part due to problems with: providing an ability to store hydrogen gas in lightweight high-pressure containers; the use of expensive noble metal catalysts to dissociate the hydrogen; and the relatively complex components needed for fuels transport. Hence, there remains a need for energy storage devices with high energy densities. Preferably, such devices may be designed to more effectively utilize hydrogen (e.g., provide hydrogen-based energy storage) while being less expensive to produce and while using more environmentally benign materials.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.